| IntroductionTelomerase is a ribonucleoprotein enzyme which is composed of RNA and protein. It can use its RNA as template to synthesize telomeric DNA sequences. It can remedy the loss of telomere after cellular mitosis, maintain telomere length and stabilize chromosome. Telomerase activity is found to be absent in most normal human somatic cells but presents in most immortalized cells and over 90% of cancer cells. Activation of telomerase in cancer cells plays a critical role in uncontrol proliferation of cells. Therefore, telomerase is regarded as a new target for cancer therapy.The regulation of telomerase activity can be expressed at various levels. Hela cells (human cervical cancer) are common cells for the study of telomerase activity. It has been testified by experiment that inhibition of telomerase activity can inhibit the growth of cancer cells, so telomerase is closely related with tumor cell growth, proliferation , senescence and carcinogenesis.Asp and Glu are two kinds of amino acids of human body. They belong to acidic amino acid and are nomal productions of protein metabolism. In pre - experiment, these two amino acids have an effect on telomerase activity of Hela cells. We do the experiment in order to find the relation of acidic amino acid and telomerase activity.Material and Method1. Material;1.1 Cell lines-. Hela cell, regular culture.1. 2 Reagents and equipment: Asp, Glu were from SIGMA company. AEBSF were purchased from Hua - Mei company. PCR kit, from Takaira company in Japan. All other chemicals were of reagent grade.CO2 incubator, Eppendorf microcentrifugal machine, Sorvall centrifugal machine ( Germany) , HRSP0520 PCR instrument ( Hybaid, USA), super clean bench,DY-l electrophoresis apparatus, etc.2. Method:2. 1 Culture of Hela cells and determination of cell number.2. 2 Treatment with various MMS concentration of MMS and for different time.2. 3 Preparation of Hela cell telomerase2.4 Determination of protein content2. 5 the activity of telomerase was examined by the method of TRAP, poly-acrylamide gel electrophoresis and silver staining. 02. 6 Statistic treatment with SPSS soft.ResultsThe effects on Hela cell proliferation with Asp at different concentration: in high concentration group (1 ~ lOmmol/L) ,the telomerase activity of Hela cell were inhibited obviously;in low concentration group ( < lmmol/L) ,there were no change compared with control group.During cell culture,the effects of Asp on telomerase activity are related to the effect time;compare with the control group, telomerase activity was down to approximately 18% as contrast to the control level at 8h. After 48h, the effect decreased gradually and approximately had no ettect after 96h.The effects on Hela cell proliferation with Glu at different concentration: in high concentration group (1 - lOmmol/L) ,the telomerase activity of Hela cell were inhibited obviously; in low concentration group ( < lmmol/L) ,there were no change compared with control group.During cell culture, the effects of Glu on telomerase activity are related tothe effect time: compare with the control group, telomerase activity was down to approximately 22% as contrast to the control level at 8h. After 48h, the effect decreased gradually and approximately had no ettect after 96h.Telomerase activity of Hela cell extract treated with acidic amino acid had no significant difference from the control group.DiscussionTelomerase is a kind of RNA - dependent DNA polymerase that elongates the telomeres of chromosome to compensate for losses that occur with each round of DNA replication. Hela cell ( human cervical cancer cell) is a kind of malignant tumor cells, telomerase of which is activated to maintain the length of te-lomere and prevent cell death. The activity of telomerase can be used as an index of measuring malignant degree of tumor. However, it is not very clear about regulation mechanism of telomerase activity.In the experiment, we investigate the effect of Asp on telomerase activity of Hela cells. As is shown above, treated with Asp at different concentrations, the telomerase activity in Hela cells is decreased to different extends, the maximum telomerase down - regulation is obtained at a concentration of lOmmol/L after Asp treatment for 8h. the results support that Asp can decrease telomerase activity of Hela cells and lead them to death.Asp changes into oxaloacetate through deamination, the latter is an important middle metabolite of tricarboxylic acid cycle (TAC) ,thus supplement of Asp can promote aerobic metabolization of tissue and accelerate mitochondria respiration. While tumor tissue acquire energy mainly by anaerobic fermentation even under the condition with adequate oxygen. Aerobic oxidation is not beneficial for growth and worsen of tumor cells. Therefore Asp is promoting agent that can inhibit growth of tumor cells.With Glu at different concentration on Hela cells, telomerase activity was inhibited. We know that Glu can change into the gamma - aminobutyric acid ( GAB A) ,the latter is the major and the best known neurotransmitter with inhibitory properties in the central nervous system (CNS). Recent study has shown...
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